41 replies to this topic

[scarab]

Magnesium is also considered as a macro nutrient. It is the basis of chlorophyll. Every single
Chlorophyll molecule has a magnesium ion in the centre.

From what I know, potassium doesn't affect calcium but I may be wrong. However, I do know that magnesium affects calcium by inhibiting it. So low magnesium can result in low calcium.

[scarab]

Also, sulphur is also a macro nutrient. Sulphates are required for the uptake of nitrates. Low sulphate results in poor nitrate uptake. Sulphur is the main structural component of cystine also is required for making the chloroplast. Chloroplast is a component of plant cells which contains chlorophyll and where photosynthesis occurs

[Mr_docfish]

Too much K (understood by some - but still not proved) can affect the uptake of Ca. But this is in severe high levels (100mg/l K or higher) and where the Ca and Mg levels are already low in the aquarium.
The trick in an aquarium - (with bright light and CO2 injection) is to maintain all the required elements in the right ratio, but higher than normally found in the wild.... if you dont have bright lighting or CO2, then these levels can be lower.

The CaSO4 is in the mix called GH booster - it is in the correct ratio for Mg:Ca:K.... understanding that K is being added in other forms in the aquarium already...

I can change the mix to suit your requirements (eg: Mg and Ca only) - but the amount of K in the GH booster is actually in lower levels than Ca and Mg... so it cannot override the Ca and Mg.

All ferts cannot work exclusively on their own - they work together - but different plant types require and use different elements differently, hence these elements can be added separately as required. When you have a mixture of plant types from different parts of the world from different ecotypes, it is hard to keep all of them happy all the time.

I can get you CaSO4 on its own..... - btw, I would not recommend the Chloride based salts like CaCl2, as this Chloride will accumulate.... Sulphates will also accumulate, but is universally accepted as bearing no issues for plant growth in high levels as compared to Chlorides.

Edited by Mr_docfish, 17 July 2011 - 08:45 PM.

[Mr_docfish]

However, I do know that magnesium affects calcium by inhibiting it. So low magnesium can result in low calcium.

Thanks for that Scarab - posted before I saw your post

This is why the GH booster contains the Ca and Mg in the right ratio.....

[waruna]

Magnesium is also considered as a macro nutrient

Hi Scarab, thank you so much for explaining this to me.. This is where the confusion was, i thought Magnesium was a Micro nutrient!! On Greg Watson's guide to dosing strategies article he has included Mg under Micros! After reading your post i did a quick search, now i am aware of all six Macros So thank you.

Hi Oliver, thanks again for the explanation, yes i'd like to get some CaSO4 by itself, what is the time frame?

The CaSO4 is in the mix called GH booster - it is in the correct ratio for Mg:Ca:K.... understanding that K is being added in other forms in the aquarium already...

I can change the mix to suit your requirements (eg: Mg and Ca only) - but the amount of K in the GH booster is actually in lower levels than Ca and Mg... so it cannot override the Ca and Mg.

Can you please give me the ratio so i can work out how much of mg, Ca and k i am putting in? Sorry for being ignorant, which mix has S? I mean from what i alreday have.. (edited this post to clarify this question)


Sorry Akamin if this is going off topic?! I'm happy to start a new thread if you want..

[waruna]

Ok Ive been trying to work out what's the best way to do this, and of course what the best ferts are..

CaSO4 comes in two forms, hemihydrate (CaSO4·~0.5H2O) which is commonly known as plaster of Paris and dihydrate (CaSO4·2H2O) which is the natural form, also known as Gypsum. CaSO4·~0.5H2O is very easy to find, i can't seem to find much Gypsum apart from here:

http://www.craftbrew...ls.asp?PID=2756

It says this is Gypsum...! What do you guys think? I'm trying to work out how much Ca to dose, CaSO4·~0.5H2O is not listed on the fertilator so i can't work this out..

http://www.aquaticpl.../fertilator.php

This is as far as my brain is taking me hehe! I'd love someone to help me out here..

Here's something interesting i read:

Hi cfreeman
Plants don’t care about ratios, so why bother. For Ca use CaSO4, harmless, cheap and efficient. Not sure what your aquarium size is so let’s say 4 tsp into 50 gallon aquarium will increase Ca to ~20 ppm. The next day test for Ca and if you need more add more. The recommended level is 20 – 30 ppm. This is easy to maintain, plants don’t uptake much. As for the GH degrees, 7.1 ppm Ca = 1 dGH.

Now about Mg. Unlike Ca, Mg is a mobile element, in a sense plants uptake much more then they actually need, so daily dose at small accurate amount works the best. Why we don’t want to add too much of it is because Mg raises dGH faster then Ca and also some plants don’t do well in higher Mg levels. We have resolved this by not adding any extra at water change except what comes with the daily PPS-Pro dose. This amount is consumed in a day not causing GH fluctuations. For information, 1 tsp MgSO4 in 50 gallon = 2.5 ppm Mg, 4.4 ppm = 1 dGH.

You can read the full thread here:
http://www.aquaticpl...ro-water-2.html

If these ratios aren't important i really like the simplicity of dosing Mg daily and Ca as needed.

Another very good article on dosing directions:

http://www.bestaquar...com/dosing.html

I'm back to where i started now, confused

[Mr_docfish]

You can use the plaster of paris - it's just a little slower at dissolving.... Ill check to see if the dihydrate is available in Perth - last time it was Ex Melbourne, and in a minimum of 25kg... I can get smaller volumes, but the price doubles for every time the volume gets halved... Ill get back to you on it...
Ill have to dig up the Ratio for Ca:Mg and the relation with K.... give me some time....

[scarab]

what units do you want it in??

Let me do it for you in terms of ppm.

1ppm = 1mg/L which means 1ppm of Ca = 1mg of Ca in 1 L of water

atomic weight of Ca = 40.078

molecular weight of CaSO4.0.5H20 = 145.14824

percentage by mass of Ca in CaSO4.0.5H2O = 40.078/145.14824 X 100% = 27.611%

1mg/L of Ca = 1/27.611 X 100% = 3.621mg/L of hemihydrate.

Hence 3.621mg of hemihydrate in 1L will raise calcium by 1ppm in 1L of water.

[waruna]

Thanks Oliver, if you can get some i'll definitely grab a kg or two.. Not bad considering you have only 23kg left to sell haha.

Hi scarab, ok i only understood the bottom sentence, i think Thank you for taking the time to explain this..

For dosing i consider my tank to be 800l. So to raise Ca level by 1ppm i need to add 2.8968g of hemihydrate?

[Mr_docfish]

I cant find my paper work I used to get my info, so I cant link you directly to where I got the details.... but from memory, the ratio is about 4:1 Ca:Mg.... but since the Magnesium is used faster than Calcium, the norm is 3:1, giving you more Mg. The K is a bit of a minor issue, and there are plenty of arguments for and against whether it can cause uptake issues, but in general, it gets used up pretty quick, and only when the levels go over 100ppm do you generally see a problem... when I find my info sheets again, Ill post it up... might have left it at work...

Oh, and Ca is heavier than Mg, so you will need to use a calculator if you only have a GH test kit and a Ca test kit - in order to be able to determine the Mg content of the GH in ppm.... but if you have a Mg test kit, then you're fine...

((17.86 x dGH) - (2.5 x Ca ppm)) / 4.1 = Mg ppm

There was a link to an automatic "fill in the box calculator" site, but I cant seem to find it - that info is on my missing sheets too.... damn

[Westie]

hmmmmm group buy anyone?
I'm keen!

[waruna]

Me too, I'll grab 2kg that leaves 20kg .. I found 25 kgs for $16, asked twice and the guy at the shop said it's def gypsum.. Asked me what i wanted it for.. Is this stuff dangerous?? BTW Jason don't expect me to go collect it lol A dark guy in his late twenties buying bulk ferts...! Mmm sounds about right haha Even though i'm not (or look) from the middle east, still You can go..

[Mr_docfish]

Well that is hell cheap - I get my stuff of a bulk chemical supply mob - if I only buy 1 bag, they slug me double that - but if I buy 10 bags, then I can talk turkey with the price..... double check the purity, make sure it is not Ag grade - Id prefer Lab or Tech grades, I normally ask for a tech sheet of the products before I choose which one..... can you get any details from him on purity?

[Westie]

BTW Jason don't expect me to go collect it lol A dark guy in his late twenties buying bulk ferts...! Mmm sounds about right haha Even though i'm not (or look) from the middle east, still You can go..

Mate as long as you don't wear a trench coat and start counting down loudly from 10 you should be safe
Yeah sounds good mate, I'm happy to play courier

[waruna]

..... can you get any details from him on purity?

Hi Oliver, the manufacturer's/brand name is Unimin.. I couldn't find much info.. I bought some (100g) from a brew shop in Bayswater on Monday, cost me $10!!!!! Not going back lol. Then i bought a bag of Plaster of Paris last night and when i started to mix that with what i had from the brew shop i realized the color was different, POP was grayish/brownish colour.. So i didn't mix the two.. I suspected POP to be not pure CaSO4?!

Finally i tracked down CaSO4·2H2O, to a brew shop in Osborne Park, BrewCraft (Contact Craig), PH (08) 9444 0468. Very helpful staff, and faxed me a Spec sheet within minutes.. 98% pure!!!! $19.00 for 1kg, which is ok considering i know what i'm paying for. I'll PM you some more info



Jase good to know i can count on you mate

[sydad]

Hello waruna,

I would recommend not using plaster of Paris. It is made from commercial gypsum by heating to a temperature sufficient to remove some of the hydrating water( 2H2O to 0.5H2O). This alters the solubility to make it less water soluble. In addition there are several things that can be added to this hemihydrate to alter the properties of the plaster. These additives include glues and glycerine (both organics), alum and borax to name just a few, and these could conceivably cause problems in the aquarium: also explains why some plasters are off-white to grey.

Syd.

[Mr_docfish]

Thanks Syd.... you can explain it better than me..... I tried some in the past to see how it worked, and it took ages to dissolve... not good - the stuff from Redox above is what I get in... now $19 for 1kg is a bit steep, but considering it is only 1kg, I can understand.... as I said above, every time you halve the 25kg bag, the price doubles...... and you think LFS are profiteering pricks??? At least I have to mix different products together, in the right ratios, then tub it, label it, provide info on dosage etc, and then clean up the mess..... that is when I feel the price is fair - but just scooping a small amount of one product into a plain bag with no instructions is just lame....

[Westie]

and you think LFS are profiteering pricks???

I was actually speaking to a couple of dudes at work about how there is bugger all margin in some LFS. Oli I don't know how you guys make any money. Especially when I see the products for sale in a certain shop in canning vale, and it's double the price in another shop (not a sponsor) for the same thing. I suppose if you started charging for all the advice I get when I come in and ask you stupid questions, you'd be a rich man and I would be somewhat poorer.
Thanks also to Syd for the advice. If this goes through as a group buy, mods should tidy up the thread and make it a sticky

Jason

[sydad]

Hey Ollie,

I agree that $19/kilo seems to be a liitle high for calcium sulphate, but it is rated "food grade", which means that it must meet appropriate analytical standards: and this means that every batch undergoes (or should) analysis. I am more than a little staggered at the level of selenium shown in the spec. sheet, but it does say maximum, so it could be much lower in fact. Either way, it should not be a problem with fish at normal usage rates.

Syd.

Edited by sydad, 21 July 2011 - 01:54 PM.

[waruna]

Hi Sydad, thanks for the heads up and taking the time to explain. It just didn't feel right mixing the food grade one with POP

It does seem a bit expensive, but i'm not sure how much is reasonable for this stuff, then again the first shop i visited was selling 50g for $5.50!!! I don't think CaSO4 is a popular ingredient in anything (apart from Tofu ha), there was only ONE guy selling Gypsum on ebay (none local, only on international ebay, business opportunity peeps lol), and it has an expiry/best before of 365 days... So who knows these sellers might have to mark up higher just so they can cover their costs, what if they only sell a couple of kg a year?! Anyway i'm pleased it's available, and locally, because it's just an eerie feeling adding stuff to the tank not knowing exactly what's in it..

Thanks to everyone for their input, i learnt a lot